[PATCH 04/25] xfs: uncached buffer reads need to return an error

From: Dave Chinner <david@fromorbit.com>
To: xfs@oss.sgi.com
Subject: [PATCH 04/25] xfs: uncached buffer reads need to return an error
Date: Thu, 25 Oct 2012 17:33:53 +1100	[thread overview]
Message-ID: <1351146854-19343-5-git-send-email-david@fromorbit.com> (raw)
In-Reply-To: <1351146854-19343-1-git-send-email-david@fromorbit.com>

From: Dave Chinner <dchinner@redhat.com>

With verification being done as an IO completion callback, different
errors can be returned from a read. Uncached reads only return a
buffer or NULL on failure, which means the verification error cannot
be returned to the caller.

Split the error handling for these reads into two - a failure to get
a buffer will still return NULL, but a read error will return a
referenced buffer with b_error set rather than NULL. The caller is
responsible for checking the error state of the buffer returned.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c     |    9 ++-------
 fs/xfs/xfs_fsops.c   |    5 +++++
 fs/xfs/xfs_mount.c   |    6 ++++++
 fs/xfs/xfs_rtalloc.c |    9 ++++++++-
 4 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 7cab1b3..62b7e89 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -715,8 +715,7 @@ xfs_buf_read_uncached(
 	int			flags,
 	xfs_buf_iodone_t	verify)
 {
-	xfs_buf_t		*bp;
-	int			error;
+	struct xfs_buf		*bp;
 
 	bp = xfs_buf_get_uncached(target, numblks, flags);
 	if (!bp)
@@ -730,11 +729,7 @@ xfs_buf_read_uncached(
 	bp->b_iodone = verify;
 
 	xfsbdstrat(target->bt_mount, bp);
-	error = xfs_buf_iowait(bp);
-	if (error) {
-		xfs_buf_relse(bp);
-		return NULL;
-	}
+	xfs_buf_iowait(bp);
 	return bp;
 }
 
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 917e121..dee14eb 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -149,6 +149,11 @@ xfs_growfs_data_private(
 				XFS_FSS_TO_BB(mp, 1), 0, NULL);
 	if (!bp)
 		return EIO;
+	if (bp->b_error) {
+		int	error = bp->b_error;
+		xfs_buf_relse(bp);
+		return error;
+	}
 	xfs_buf_relse(bp);
 
 	new = nb;	/* use new as a temporary here */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index d39ad72..dc51e32 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -658,6 +658,12 @@ reread:
 			xfs_warn(mp, "SB buffer read failed");
 		return EIO;
 	}
+	if (bp->b_error) {
+		error = bp->b_error;
+		if (loud)
+			xfs_warn(mp, "SB validate failed");
+		goto release_buf;
+	}
 
 	/*
 	 * Initialize the mount structure from the superblock.
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index b271ed9..98dc670 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1876,6 +1876,11 @@ xfs_growfs_rt(
 				XFS_FSB_TO_BB(mp, 1), 0, NULL);
 	if (!bp)
 		return EIO;
+	if (bp->b_error) {
+		error = bp->b_error;
+		xfs_buf_relse(bp);
+		return error;
+	}
 	xfs_buf_relse(bp);
 
 	/*
@@ -2221,8 +2226,10 @@ xfs_rtmount_init(
 	bp = xfs_buf_read_uncached(mp->m_rtdev_targp,
 					d - XFS_FSB_TO_BB(mp, 1),
 					XFS_FSB_TO_BB(mp, 1), 0, NULL);
-	if (!bp) {
+	if (!bp || bp->b_error) {
 		xfs_warn(mp, "realtime device size check failed");
+		if (bp)
+			xfs_buf_relse(bp);
 		return EIO;
 	}
 	xfs_buf_relse(bp);
-- 
1.7.10

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